1. Field of the Invention
The invention relates to a disk brake.
2. Description of the Prior Art
From published German Patent Disclosure DE 1 480 005 A1, a disk brake is known, with a brake piston and with a friction brake lining that can be pressed by the brake piston against a brake disk for actuating the disk brake. The brake piston of the known disk brake acts transversely to the brake disk. The friction brake lining is displaceable transversely and parallel to the brake disk, the term “parallel” meaning a displacement in a circumferential or secant direction to the brake disk. The friction brake lining of the know disk brake is braced against a displacement parallel to the brake disk on an auxiliary piston, which like the friction brake lining is displaceable parallel to the brake disk. The auxiliary piston communicates with the brake piston.
If for actuation of the disk brake the friction brake lining is pressed against the rotating brake disk, the brake disk exerts a frictional force in its direction of rotation on the friction brake lining that is pressed against it. The friction brake lining is displaced in the direction of rotation of the brake disk and is braced on the auxiliary piston, which as a result is displaced into a cylinder bore in a brake caliper and generates a hydraulic pressure. Since the auxiliary piston communicates with the brake piston, the hydraulic pressure is transmitted to the brake piston, which presses the friction brake lining against the brake disk. Viewed in static terms, the same pressure acts on the auxiliary piston and on the brake piston; a ratio of the piston forces of the auxiliary piston and brake piston is equal to the inverse ratio of the piston faces that are acted upon hydraulically. The auxiliary piston and the brake piston communicating with it form a hydraulic self-boosting device, which utilizes the frictional force, exerted on the friction brake lining pressed against the brake disk by the rotating brake disk when the disk brake is actuated, as an auxiliary force for pressing the friction brake lining against the brake disk and as a result increasing a braking force of the disk brake.